Evaluating the effects of green manure and biofertilizers on pak choi yield, minerals, and phytonutrient contents

Evaluating the effects of green manure and biofertilizers on pak choi yield, minerals, and phytonutrient contents

Summary

Summary

The first phase of this research was conducted from October to December 2015, to evaluate the application of biofertilizer(s) on the growth and development of pak choi (Brassica rapa chinensis). Eight treatments (Control, Vesicular-Arbuscular Mycorrhizae, Azospirillium, Trichoderma, Vesicular-Arbuscular Mycorrhizae + Trichoderma,  Azospirillium + Trichoderma, Vesicular-Arbuscular Mycorrhizae + Azospirillium, Vesicular-Arbuscular Mycorrhizae + Azospirillium + Trichoderma) were used to inoculate potting mix (Pro-mix with Mycorrhizae) in which pak choi was grown under greenhouse condition. All treatments were analyzed and compared to the control using Statisix 9. Analysis of variance (ANOVA) and Tukey’s HSD test. Result showed that all seven treatments produce lower leaf yield when compared to the control Trichoderma + Azospirillium, Trichoderma + Azospirillium + Vesicular-Arbuscular Mycorrhizae, and Vesicular-Arbuscular Mycorrhizae + Azospirillium produced significantly lower yields, whereas the others were not significantly different from the control. Pro-mix with mycorrhizae by itself produce higher leaf yield. There was a significant different in root dry weight among treatments. Trichoderma and Azospirillium had the highest root dry weight. Further greenhouse studies will be conducted to determine the effects of biofertilizers on crop growth and development and to identify the elite biofertlizer(s) to use in the proposed field study.

Objectives/Performance Targets

Objectives/Performance Targets

1. Investigate the use of green manure and biofertilizers in growth and development of pak choi.
2. Evaluate the use of green manure and biofertilizers to increase minerals and phytonutrients contents in pak choi.

Both objectives remain in progress as stated. In order to satisfy both objectives we have conducted a greenhouse study to screen and select elite biofertilizer(s) using yield data collected from the pak choi experiment. This study will be repeated in the spring to verify our findings in order to conduct the field study. Once elite biofertilizer inoculant(s) is identified the objectives will be met.

Accomplishments/Milestones

A pak choi study was conducted during fall 2015. The study was conducted in a greenhouse in a complete randomized design with seven biofertilizer treatments and the control, with four replicates each.  Pro-mix with mycorrhizae was inoculated with the biofertilizer treatments according to the manufacturer’s instructions for all treatments. Inoculated potting mix was placed into 6’ pots and two pak choi seeds were planted in each. One seedling was removed 5 days after germination; leaving one plant per replicate. Plants were watered when needed and fertilized with 500 ml of 20:20:20 foliar fertilizer once per week. After 3 weeks, the plants were transferred to 2.5 gallon pots fill with inoculated potting mix. Four weeks later plant were harvested, leaf yield was collected and recorded. Roots were placed to dry for 96 hours at 70 ºC and the dry weight collected. Data was analyzed and recorded.
Result showed that all seven treatments produce lower leaf yield when compared to the control Trichoderma + Azospirillium, Trichoderma + Azospirillium + Vesicular-Arbuscular Mycorrhizae, and Vesicular-Arbuscular Mycorrhizae + Azospirillium produced significantly lower yields, whereas the others were not significantly different from the control. Pro-mix with mycorrhizae by itself (Control) produce higher yield (Table 1). There was a significant difference in root dry weight among treatments. Trichoderma + Azospirillium had the highest root dry weight when compared to the other treatments (Table 2). Therefore, it is a possibility that this result is affected by competition among microorganisms. The three treatments that have produce significantly lower yield than the control showed that they all are a combination of Vesicular-Arbuscular Mycorrhizae. However, Vesicular-Arbuscular Mycorrhizae by itself showed no significant difference when compared to control. The need for further study using other potting mix, for example one without mycorrhizae, to determine the impact microbial communities have on crop yield.

Table 1. Pak Choi Yield

*Means (n=4) followed by the same letters are not significantly different according to Tukey’s HSD test at 5% probability.

Table 2. Root Dry Weight

*Means (n=4) followed by the same letters are not significantly different according to Tukey’s HSD test at 5% probability.

Impacts and Contributions/Outcomes

This project is in its initial stages; therefore, a definite outcome cannot be determine as yet. However, our greenhouse experiment has revealed how biofertilizers may impact the growth and development of a vegetable crop. Evaluating the impact of biofertilizers on crop yield is necessary to select elite biofertilizers to use in sustainable agricultural systems.

Collaborators: